Patients prefer AZ's Symbicort to Advair in study

LONDON, May 20 (Reuters) - Patients with asthma prefer AstraZeneca Plc's (AZN.L) drug Symbicort to GlaxoSmithKline Plc's (GSK.L) Advair, according to results of a clinical study backed by AstraZeneca released on Tuesday.

Both drugs have a similar mode of action, combining a corticosteroid and a long-acting beta-agonist, and compete in the multibillion-dollar asthma market.

Results of an open-label study presented at the International Conference of the American Thoracic Society in Toronto found adults with moderate to severe asthma favoured Symbicort administered as an adjustable dose over Advair.

They reported greater satisfaction for timely relief of symptoms and feeling the medicine begin to work, Dr. Richard O'Connor of the University of California-San Diego said.

The adjustable dose of Symbicort is available in 87 countries as a maintenance and acute relief therapy -- but not the United States, where it was only launched as a long-term maintenance treatment last year.

Advair is Glaxo's top seller, with global sales of 3.5 billion pounds ($6.84 billion) in 2007. Symbicort is a smaller product, selling $1.6 billion last year. (Reporting by Ben Hirschler; Editing by Quentin Bryar)